Initiation and Regulation of Prophenoloxidase Activation

原酚氧化酶激活的启动和调节

• 批准号: 7025646
• 负责人: HAOBO JIANG
• 金额: $ 22.23万
• 依托单位: OKLAHOMA STATE UNIVERSITY STILLWATER
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7025646
• 关键词: Manduca; cofactor; complementary DNA; endopeptidases; enzyme activity; enzyme induction /repression; hemolymph; microorganism immunology; molecular cloning; monophenol monooxygenase; protein sequence; recombinant proteins; serine proteinases

DESCRIPTION (provided by applicant): The prophenoloxidase activation pathway in insects is an integral component of the host immune system against microbial infection. Phenoloxidase (PO) catalyzes the production of quinones that are precursors for cuticle sclerotization, wound healing, and melanotic encapsulation of invading microorganisms. Due to high reactivity and cytotoxicity of quinones, proteolytic activation of prophenoloxidase (PPO) has to be tightly regulated as a potent, local reaction against nonself. In insect vectors of human diseases, initiation and control of this process may be interfered by proteins from pathogens or parasites. Knowledge of the activation process from biochemical model insects such as Manduca sexta will be useful for understanding and manipulating a similar system in blood-feeding insects that transmit human diseases. Three PPO-activating proteinases (PAPs) isolated from M. sexta require cleaved serine proteinase homologs (SPHs) for PPO activation. Molecular cloning and sequence comparison indicate that the PAPs and SPHs all contain regulatory clip domains. We plan to expand our current research on PAPs to acquire in-depth understandings of the molecular mechanisms that trigger and regulate the PPO activation in M. sexta. The specific aims of this project are: 1) Characterization of HP14, an initiation proteinase of the PPO activation cascade; 2) Isolation and cDNA cloning of an activating enzyme for proSPH-1 and proSPH-2; 3) Functional analysis of the clip domains in PAP-2.

描述（由申请人提供）：昆虫中的酚氧化酶原激活途径是宿主免疫系统抵抗微生物感染的重要组成部分。酚氧化酶 (PO) 催化醌的产生，醌是角质层硬化、伤口愈合和入侵微生物黑色素包裹的前体。由于醌的高反应性和细胞毒性，酚氧化酶原 (PPO) 的蛋白水解激活必须受到严格调节，作为针对异体的有效局部反应。在人类疾病的昆虫媒介中，这一过程的启动和控制可能会受到来自病原体或寄生虫的蛋白质的干扰。了解天蛾等生化模型昆虫的激活过程将有助于理解和操纵传播人类疾病的吸血昆虫的类似系统。从 M. sexta 中分离出的三种 PPO 激活蛋白酶 (PAP) 需要裂解的丝氨酸蛋白酶同源物 (SPH) 才能激活 PPO。分子克隆和序列比较表明PAP和SPH均含有调控片段结构域。我们计划扩大目前对 PAP 的研究，以深入了解触发和调节 M. sexta 中 PPO 激活的分子机制。该项目的具体目标是： 1) HP14 的表征，HP14 是 PPO 激活级联的起始蛋白酶； 2) proSPH-1和proSPH-2激活酶的分离和cDNA克隆； 3) PAP-2 中剪辑域的功能分析。